Steam generator and superheater.



No. 798,327. PATENTED AUG. 29, 1905. B. E. ELDRED.

STEAM GENERATOR AND SUPERHEATER.

APPLICATION FILED MAR.17, 1905.

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No. 798,327. PATENTED AUG. 29,- 1905.

' B. E. ELDRBD, STEAM GENERATOR AND SUPERHEATER.

APPLICATION FILED MAR. 17, 1905.

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No. 798,327. PATENTED AUG. 29, 1905 B. E. ELDRBD.

STEAM GENERATOR AND SUPBRHEATER.

APPLICATION FILED MAR. 17, 1905.

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WITNESSES NVENTOR 94v. 24m M wfia; ATTORNEYS UNITED STATES PATENT OFFICE.

Specification of Letters Patent.

Patented Aug. 29, 1905.

' Application filed March 17, 1905. Serial No. 250,574.

To all whom it may concern.-

Be it known that I, BYRON E. ELDRED, a citizen of the United States, residing at Bronxville, county of Westchester, State of New York, have invented certain new and useful Improvements in Steam Generators and Superheaters, of which the following specification and accompanying drawings disclose as an'illustration one embodimentthereof which I- now regard as the best out of the various forms in which the principles of my invention may be applied.

This invention relates to generating and superheating steam according to a new method in which the water or steam, or both, are subjected to the heating influence of a modified flame, which may be a comparatively cool flame. The flame is preferably produced, according to the method described in my Patent No. 692,257, by carryinga small portion of the products of combustion through the fuel-bed under accelerated draft to render the flame inflated and slow-burning and also keep down the temperature of the fire-box.

It has heretofore been inadvisable to place superheaters directly in the path of the hottest flame from a steam-boiler furnace, both on account of the overheating of the steam,

which tends to injure the engine and interfere with its lubrication, and on account of the oxidizing and destructive effect on the superheater. As respects the superheating feature of my invention, I am enabled to avoid these difficulties by making the flame which affects the superheater comparatively cool.

The invention includes a novel means for developing a flame of this character for either vaporizing water or superheating steam. In using the diluent-inflated flame it is necessary to take into account the relatively cold condition of the boiler-surfaces, especially in view of the retarded combustion of said flame. I have devised certain means for minimizing this chilling efl ect, the characteristic feature of which consists in a novel expedient for preventing undue contact of the flame with the cool boiler or superheater surfaces and causing the heating to be accomplished largely by radiation. Such expedient as herein shown involves the provision of reverberative heatretaining surfaces arranged, preferably, in a tier, in combination with evaporating or superheating chambers on the under side of the flame-channel. The natural tendency of the flame to hug the roof of its channel therefore results in protecting it to a large extent from premature chilling by the water or vaporcooled surfaces, the vaporizing or superheating chambers being heated largely by radiated and reverberated heat. These reverberative surfaces are made of fire-clay and serve to retain the heat and sustain the ignition of the flame until its combustion is substantially complete.

Of the accompanying drawings, Figure 1 represents a longitudinal vertical section of a flash-boiler and furnace constructed according to my invention. Fig.2 represents a front elevation and transverse section thereof on the line 2 2 of Fig. 3. Fig. 3 represents a plan and horizontal section on the line 3 3 of Fig. 2.

The same reference characters indicate the same parts in all figures.

The drawings show a construction which practically consists of three generators, although plurality is not essential. Each is provided with a grate 1 for burning solid fuel, an ash-pit 2 below the grate, and a firechamber 3 above the same continued in the form of an elongated sinuous passage or combustion and heating chamber consisting of horizontal stretches 1 5 6 and short vertical connecting-passage 7 8, forming a continuous flue structure leading to the stack or waste-gas flue 10. The three units are connected by branches 38 with this flue.

In the upper part of the casing of each unit is located a preheater, comprising pipes 11 and headers 12, into which the feed-water is pumped or fed from a feed-pipe 13 by branch 22 and maintains a back-and-forth circulation until it reaches an oiftake-pipe 14 at the upper end of the group. This pipe is continued downwardly at 15 to the lowermost one of a series of multitubular vaporizing and superheating chambers 16, located on the floors or lower sides of the horizontal stretches'5 5 of the flame and gas flue. In each of these chambers the circulation is back and forth in a horizontal direction and finally through a riser 17 to the next chamber above, the final discharge being through a pipe 18 toa steam-drum 19. The several drums areshown connected to a steam-pipe 37. Each drum has a safety-valve 20.

Refractory fire-brick baflles or arches 21, projecting outwardly from the front and rear of the fire-brick walls of the generator-casing, form the roofs of the horizontal stretches or IIO channels 5, the floors being formed by the vaporizing and superheating chambers 16.

Thinner baflles 23 are interposed between the tubes 11 of the preheater and serve to direct 5 the gases in a sinuous path thereamong.

In the tubes 11 of the preheater the water is brought to or toward theboiling-point, and in the lower chamber or chambers 16 of the flash-boiler it is vaporized. In the upper I chambers 16 the steam is superheated. In

the pipe 14, connecting the preheater with the flash-boiler, is placed a safety-valve 24. There is also located in this pipe a valve 25, controlled by a regulator 26, connected with 5 the flash-boiler througha pipe 27. This regulator may operate according to the pressure or according to the temperature of the contents of the flash-boiler or may be any other suitable regulator for controlling the feed to 20 a flash-boiler.

28 is a tunnel connecting by openings 29 with the several ash-pits 2 and receiving the delivery of a fan-blower 30. The suction-.

pipe 31 of said blower connects with the stack 5 10 and is provided with an air-inlet 32 for supplying air to support the combustion of the fuel. This air-inlet and the trunk of the pipe 31' are provided with valves or dampers 33 3 1 for independently regulating the pro- 3 portions of stack-gases and air in the draftcurrent supplied to the fires. Each ash-pit aperture 29 also has its valve or damper 35 for regulating the respective portions of the total draft going to the several ash-pits.

35 7 In operation the neutral gr inert products iof combustion in the draft-current serve'to produce a long slow-burning comparatively f cool flame and keep down the temperature of the fire-box evenunder accelerated draft.

4 The combustion of the flame is greatly retarded and takes place largely in the fluepassages 4 5 7. The ignition of this flame is maintained by the reverberative arches 21, to which the flame tends to cling and is thereby kept from intimate contact with the water or steam cooled chambers 16. In this way its complete combustion and the liberation of the heat over a large area are insured. The heating of the chambers 16 is largely by radia- 5 tion from the flame and from the reverberative surfaces heated thereby, and owing to the comparative coolness of the flame and the described manner of guiding it the superheating-chambers are protected from injury and from liability to overheating of their contacts. The combustion may, if desired, be 10- calized and intensified at a predetermined point by means of air-jets; but this I have claimed in a separate application, Serial No. 233,241.

In a steam-generator employing an inflated slow-burning flame, as described, a special reason exists for having the coldest water farthest from the fire-box, because this avoids 5 the tendency to premature chilling of any flame that may come in contact with the cold surfaces. Since the flame is greatly elongated by the neutral stack-gases, a preheater placed as described may receive much more heat than a preheater similarly placed in an ordinary boiler-furnaCe. It may be so arranged as to absorb practically all of the sensible heat remaining in the flue-gases. The cooling of the latter willnot interfere with draft, since the draft is maintained mechanically.

I have further shown a by-pass or branch flue 39 leading from the fire-chamber 3, (to the stack or chimney) whereby the flame may at times be wholly or partly diverted from the boiler and superheaterpassages, as in starting or when too much heat is being applied.

Ido not, of course, restrict my invention to the exact construction shown, as the idea of heating by a superincumbent flame of the described character may be embodied in many diflerent forms of apparatus. missible to use different kinds of fuels suited to the particular evaporative or heating effects desired and having burner apparatus suited to their particular character or physical condition, such as liquid, gaseous, powdered fuel, &c. The particular burneri. e., the structure employed for bringing the fuel and air into combusting relation-here shown is a grate and its appurtenant ash-pit and walls; but for fuels other than the ordinary solid fuel bed different burners would of course be used.

What Iclaim as new, and desire to secure by Letters Patent, is v 1. In steam apparatus, the combination of a furnace provided with a burner for fuel and air, means to supply and pass through the burner a diluentfixed gas for inflating and lengthening the flame, a flame-channel emanating from the burner, a superheating-channher in said channel, and means to supply steam to said chamber.

2. In steam apparatus, the combination of a furnace provided with a burner for fuel and air, means to supply and pass through the burner a diluent fixed gas for inflating and lengthening the flame, a flame-channel emanating from the burner and having a roof suited to maintain the ignition of the inflated flame, and a pressure-chamber for water or steam in the lower portion of said flame-channel adapted to be heated largely by radiation from the flame and the roof of the flamechannel.

It is also per-v 3. In steam apparatus, the combination of a steam in sections occupying the lower portions of saidpassages and provided with induction and eduction pipes.

4:. In steam apparatus, the combination of a furnace including a seat of combustion and a flame-channel, a waste-gas flue, a return-conduit connecting said waste-gas flue with the draft-chamber of the furnace for supplying diluent products of combustion to pass through the seat of combustion, means to supply air to said seat, a refractory wall roofing said flame-channel, and a pressure-chamber for water or steam under said wall on the opposite side of the flame-channel therefrom.

5. The combination of a furnace having a sinuous flame-channel composed of a tier of connected flame-passages, refractory roofs for said passages, pressure-chambers in'the lower portions of said passages, a fire-box forming part of said furnace and having a seat of initial combustion and a draft-chamber anterior thereto, means to supply to said chamber a draft-current of products of combustion and and means to supply to the fire-box an accelerated draft-current of air and products of combustion in predetermined proportions for initiating and lengthening the flame and cooling the fire-box.

In witness whereof I have hereunto set my hand this 1st day of March, 1905.

BYRON E. ELDRED. Witnesses:

JAs. K. CLARK, CARLn'roN ELLIs. 

